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#1
06/10/2004, 09:53 AM
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Using UV "black-light" to test for the presence of phosphates.
For several years now I have been using fluorescent "blacklights" to test for the presence of phosphates in my aquariums.
I test the water in large glasses, one with distilled water and the other with tank water. When present and exposed to the light the water will glow similar to tonic water. The distilled glass will be clear. Make sure your glasses/conatiners are clear under black-light to begin with though. I have tested well water before and it looked like it came from Chernobyl. I have also placed the light over my tanks before and my old freshwater tanks glowed the most. As soon I saw any sign of glowing in my SW tanks (which was not very often) I did a water change and it was clear again. I know there are test kits out there but found this to be a cheap alternative for testing. You can also use it to test frozen seafoods. As they thaw the water around the food begins to glow. I would then drain this water off before feeding. If you have a "fluorescent" black-light hanging around you might want to give it a try. Next up is trying a test on an older established DSB vs a younger one, but that won't be for awhile.
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"Just a drop in the bucket" Last edited by Aquabucket; 06/10/2004 at 10:19 AM. |
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#2
06/10/2004, 09:59 AM
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Were you able to make the glow go away with phos-ban or some other phosphate absorber/precipitator for confirmation that the PO4 was indeed the glowing agent?
I have an old magneflux testor lamp that makes insects wig out. It is some boowah!!! UV, far more wicked than the old Spencer's Gifts blacklight. This sounds like this will be a very cool PO4 test technique if it really works like this.  What will y'all come up with next?? (I can't wait)
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#3
06/10/2004, 10:32 AM
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Quote:
You want to stick with a "BLB" (black light blue, ie Spencers) bulbs as bug lights and "BL" bulbs have more visual light. BTW I sold about a half million of my light sculptures through Spencers. I have found that phosphates have a distinct visual fingerprint under UV. Its kind of like a muted anti-freeze or tonic water. Other things that tend to fluoresce have a different intensity and color. The closest thing I found to look like phosphates is quinine, but after you compare the two you can see the difference. I never tested water after using Phosban, etc.. You might want to give it shot. All I know for sure is this, Phosphates can not escape detection under strong UV.
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#4
06/10/2004, 12:35 PM
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Quote:
But more to the point: What colour does the phosphate appear to flouresce in? It would be nice to have absorption and emission spectra for phosphate in water. Anyone have a book or ref? If you are correct, and phosphate is the dominant fluorescent contributor, the simple UV method should be a good alternative to laborious test kits, even for the hobbyist. Therefore, a test on SW aquarium water samples with known phosphate concentrations is needed, along with a practical form of quantisation of the measurement results. A confirmed cheap UV light source would also be nice for DIY. Fluorescence spectroscopy is used in industry to detect several different compounds in water, but that kind of equipment is not practical (economically) to the general hobbyist. sorenb |
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#5
06/10/2004, 12:54 PM
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Quote:
The phosphates kinda glow like watered down anti-freeze. I admit its hard to get an accurate concentration this way and more experiments are needed, but it can be an accurate form of detection I think.
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